runtests.sh does not work on Windows

Describe the bug
Trying to run tests on a Windows machine, as per the PR template, does not work. The obvious problem is that my python path has spaces in it.

To Reproduce
Steps to reproduce the behavior:

Dzenan@Ryzenator MINGW64 /m/Dev/MONAI (dev)
$ ./runtests.sh -f -u --net --coverage
./runtests.sh: line 115: /c/Program: No such file or directory
./runtests.sh: line 116: [: : integer expression expected
PYTHONPATH: /m/Dev/MONAI:
Python: /c/Program Files/Python39/python
./runtests.sh: line 123: /c/Program: No such file or directory

Expected behavior
Tests are run, similarly to a Linux machine.

Environment

Dzenan@Ryzenator MINGW64 /m/Dev/MONAI (dev)
$ python -c 'import monai; monai.config.print_debug_info()'
C:\Program Files\Python39\lib\site-packages\requests\__init__.py:102: RequestsDependencyWarning: urllib3 (1.26.6) or chardet (5.0.0)/charset_normalizer (2.0.4) doesn't match a supported version!
  warnings.warn("urllib3 ({}) or chardet ({})/charset_normalizer ({}) doesn't match a supported "
================================
Printing MONAI config...
================================
MONAI version: 1.1.0+25.g11810a3e.dirty
Numpy version: 1.21.2
Pytorch version: 1.12.0+cu116
MONAI flags: HAS_EXT = False, USE_COMPILED = False, USE_META_DICT = False
MONAI rev id: 11810a3e61c8a60034df5a12d336578705ae6052
MONAI __file__: M:\Dev\MONAI\monai\__init__.py

Optional dependencies:
Pytorch Ignite version: NOT INSTALLED or UNKNOWN VERSION.
ITK version: 5.3.0
Nibabel version: 3.2.1
scikit-image version: 0.18.3
Pillow version: 9.2.0
Tensorboard version: 2.6.0
gdown version: NOT INSTALLED or UNKNOWN VERSION.
TorchVision version: 0.13.0+cu116
tqdm version: 4.62.2
lmdb version: NOT INSTALLED or UNKNOWN VERSION.
psutil version: 5.8.0
pandas version: 1.3.2
einops version: NOT INSTALLED or UNKNOWN VERSION.
transformers version: NOT INSTALLED or UNKNOWN VERSION.
mlflow version: NOT INSTALLED or UNKNOWN VERSION.
pynrrd version: NOT INSTALLED or UNKNOWN VERSION.

For details about installing the optional dependencies, please visit:
    https://docs.monai.io/en/latest/installation.html#installing-the-recommended-dependencies


================================
Printing system config...
================================
System: Windows
Win32 version: ('10', '10.0.22621', 'SP0', 'Multiprocessor Free')
Win32 edition: Professional
Platform: Windows-10-10.0.22621-SP0
Processor: AMD64 Family 25 Model 33 Stepping 0, AuthenticAMD
Machine: AMD64
Python version: 3.9.13
Process name: python.exe
Command: ['C:\\Program Files\\Python39\\python.exe', '-c', 'import monai; monai.config.print_debug_info()']
Open files: [popenfile(path='C:\\Windows\\System32\\en-US\\tzres.dll.mui', fd=-1), popenfile(path='C:\\Windows\\System32\\en-US\\KernelBase.dll.mui', fd=-1), popenfile(path='C:\\Windows\\System32\\en-US\\kernel32.dll.mui', fd=-1)]
Num physical CPUs: 12
Num logical CPUs: 24
Num usable CPUs: 24
CPU usage (%): [0.0, 0.0, 11.5, 0.4, 6.0, 7.7, 0.0, 0.2, 1.9, 0.2, 0.2, 0.6, 1.1, 0.4, 0.0, 0.2, 0.0, 0.0, 0.0, 0.0, 0.2, 2.6, 0.0, 0.0]
CPU freq. (MHz): 3001
Load avg. in last 1, 5, 15 mins (%): [0.0, 0.0, 0.0]
Disk usage (%): 52.3
Avg. sensor temp. (Celsius): UNKNOWN for given OS
Total physical memory (GB): 63.9
Available memory (GB): 34.6
Used memory (GB): 29.3

================================
Printing GPU config...
================================
Num GPUs: 1
Has CUDA: True
CUDA version: 11.6
cuDNN enabled: True
cuDNN version: 8302
Current device: 0
Library compiled for CUDA architectures: ['sm_37', 'sm_50', 'sm_60', 'sm_61', 'sm_70', 'sm_75', 'sm_80', 'sm_86', 'compute_37']
GPU 0 Name: NVIDIA GeForce RTX 3090
GPU 0 Is integrated: False
GPU 0 Is multi GPU board: False
GPU 0 Multi processor count: 82
GPU 0 Total memory (GB): 24.0
GPU 0 CUDA capability (maj.min): 8.6

Start by inspecting runtests.sh around lines 115-123, where the Python path is invoked and the reported errors occur. Reproduce the command under Windows with Python installed in a path containing spaces; done means the test command runs successfully there as it does on Linux.