cmd/test*: fail with error while loading shared libraries: libhdf5_serial.so.10: cannot open shared object file: No such file or directory

### What are you trying to do?
Run tests.

### What did you do?
```
git checkout 847297cb569e6bb5d2ef9248b222eb4d8d40bd2d
GODEBUG=cgocheck=0 go test ./...
```

### What did you expect to happen?
Successful test completion.

### What actually happened?
```
$ GODEBUG=cgocheck=0 go test ./...
ok gonum.org/v1/hdf5 (cached)
--- FAIL: TestCpxCmpd (0.00s)
main_test.go:24: error: exit status 127
test-go-cpxcmpd: error while loading shared libraries: libhdf5_serial.so.10: cannot open shared object file: No such file or directory

FAIL
FAIL gonum.org/v1/hdf5/cmd/test-go-cpxcmpd 0.004s
? gonum.org/v1/hdf5/cmd/test-go-extend-ds [no test files]
? gonum.org/v1/hdf5/cmd/test-go-hdf5 [no test files]
--- FAIL: TestTableRWCmd (0.00s)
main_test.go:25: error: exit status 127
test-go-table-01: error while loading shared libraries: libhdf5_serial.so.10: cannot open shared object file: No such file or directory

FAIL
FAIL gonum.org/v1/hdf5/cmd/test-go-table-01 0.004s
? gonum.org/v1/hdf5/cmd/test-go-table-01-readback [no test files]
ok gonum.org/v1/hdf5/cmem (cached)
FAIL
```

### What version of Go, Gonum, Gonum/netlib and libhdf5 are you using?

Gonum: 1d8f8b2ee4cec2e174d8abadec9339ec4961b303
HDF5: 847297cb569e6bb5d2ef9248b222eb4d8d40bd2d
Go version: go version go1.13 linux/amd64

### Does this issue reproduce with the current master?
Yes

### Additional information

The system-wide install provides a `libhdf5_serial.so.100.0.1`.

```
$ dpkg -L libhdf5-100
/.
/usr
/usr/lib
/usr/lib/x86_64-linux-gnu
/usr/lib/x86_64-linux-gnu/libhdf5_serial.so.100.0.1
/usr/lib/x86_64-linux-gnu/libhdf5_serial_fortran.so.100.0.1
/usr/lib/x86_64-linux-gnu/libhdf5_serial_hl.so.100.0.0
/usr/lib/x86_64-linux-gnu/libhdf5_serialhl_fortran.so.100.0.0
/usr/share
/usr/share/doc
/usr/share/doc/libhdf5-100
/usr/share/doc/libhdf5-100/changelog.Debian.gz
/usr/share/doc/libhdf5-100/copyright
/usr/share/lintian
/usr/share/lintian/overrides
/usr/share/lintian/overrides/libhdf5-100
/usr/lib/x86_64-linux-gnu/libhdf5_serial.so.100
/usr/lib/x86_64-linux-gnu/libhdf5_serial_fortran.so.100
/usr/lib/x86_64-linux-gnu/libhdf5_serial_hl.so.100
/usr/lib/x86_64-linux-gnu/libhdf5_serialhl_fortran.so.100
/usr/share/doc/libhdf5-100/RELEASE.txt.gz
```

Start by running GODEBUG=cgocheck=0 go test ./... at the reported HDF5 revision, then inspect cmd/test-go-cpxcmpd/main_test.go and cmd/test-go-table-01/main_test.go along with their test binaries' shared-library requirements. Done means both failing command tests and the full suite complete successfully with the installed HDF5 library.

Written by the indexing model from the issue text.