DrMemory ci-windows vs2019-32 and vs2019-64 exit without running any tests

ci-winwows vs2019-32 and vs2019-64 exit without running any tests with the following errors:

```
FAILED: tests/CMakeFiles/hello.dir/hello.c.obj
C:\PROGRA~2\MICROS~2\2019\ENTERP~1\VC\Tools\MSVC\1429~1.301\bin\Hostx86\x86\cl.exe /nologo -DASSEMBLE_WITH_MASM -DBUILD_NUMBER=1 -DDEBUG -DDR_HOST_X86 -DDR_LOG_DEFINE_COMPATIBILITY -DDR_PAGE_SIZE_COMPATIBILITY -DSTATISTICS -DTOOL_DR_MEMORY -DVERSION_COMMAS=2,6,20167 -DVERSION_NUMBER=2.6.20167 -DVERSION_STRING=\"2.6.20167\" -DWINDOWS -DX86 -DX86_32 -D_X86_ -ID:\a\drmemory\drmemory\wininc\psdk -ID:\a\drmemory\drmemory\wininc\dxsdk -ID:\a\drmemory\drmemory\build_drmemory-dbg-32\dynamorio\cmake -ID:\a\drmemory\drmemory\build_drmemory-dbg-32\dynamorio\cmake\..\include -ID:\a\drmemory\drmemory\build_drmemory-dbg-32\dynamorio\ext\include -ID:\a\drmemory\drmemory\common -ID:\a\drmemory\drmemory\drmemory -ID:\a\drmemory\drmemory\third_party\valgrind -ID:\a\drmemory\drmemory\build_drmemory-dbg-32\drmf\include -ID:\a\drmemory\drmemory\tests\..\third_party\valgrind /DWIN32 /D_WINDOWS /MT /Zi /Ob0 /Od /W2 /WX /GS- /MP /FS -Wno-all /showIncludes /Fotests\CMakeFiles\hello.dir\hello.c.obj /Fdtests\CMakeFiles\hello.dir\ /FS -c D:\a\drmemory\drmemory\tests\hello.c
cl : Command line error D8021 : invalid numeric argument '/Wno-all'
:
ninja: build stopped: subcommand failed.
Command exited with the value: 1
:
drmemory-dbg-32: build successful; no tests for this build
```

The jobs are green even with the above errors, and no tests being ran.