library frames missing from callstacks in suppress test

On Github Actions Server2016 in the "suppress" test:

The call_into_bar callstack is supposed to be suppress, but it's missing
several frames from suppress-mod-bar.dll. The call_into_foo callstack is
supposed to be a reported error, but it's missing several frames from
suppress-mod-foo.dll. Somehow all those library frames are just missing.

This may be related to #2064: missing frames in 64-bit Windows callstacks with VS2017 ucrt
One solution may be #1222: on win64, use SEH unwind tables to walk callstack

```
2020-12-07T05:22:55.7697393Z Error #2: UNINITIALIZED READ: reading register eax
2020-12-07T05:22:55.7698021Z # 0 suppress.exe!do_uninit_read (0x00007ff7c109102a )
2020-12-07T05:22:55.7698614Z d:\a\drmemory\drmemory\tests\suppress.c:63
2020-12-07T05:22:55.7699203Z # 1 suppress.exe!do_uninit_cb (0x00007ff7c109160a )
2020-12-07T05:22:55.7699848Z d:\a\drmemory\drmemory\tests\suppress.c:261
2020-12-07T05:22:55.7700441Z # 2 suppress.exe!call_into_bar (0x00007ff7c1091646 )
2020-12-07T05:22:55.7701043Z d:\a\drmemory\drmemory\tests\suppress.c:269
2020-12-07T05:22:55.7701705Z # 3 suppress.exe!mod_ellipsis_test (0x00007ff7c1091733 )
2020-12-07T05:22:55.7702517Z d:\a\drmemory\drmemory\tests\suppress.c:325
2020-12-07T05:22:55.7703364Z # 4 suppress.exe!test (0x00007ff7c109189c )
2020-12-07T05:22:55.7704144Z d:\a\drmemory\drmemory\tests\suppress.c:379
2020-12-07T05:22:55.7704861Z # 5 suppress.exe!main (0x00007ff7c1091919 )
2020-12-07T05:22:55.7705586Z d:\a\drmemory\drmemory\tests\suppress.c:398
2020-12-07T05:22:55.7706078Z Note: @0:00:03.401 in thread 1948
2020-12-07T05:22:55.7706531Z Note: instruction: test %eax %eax
2020-12-07T05:22:55.7706860Z
2020-12-07T05:22:55.7707344Z Error #3: UNINITIALIZED READ: reading register eax
2020-12-07T05:22:55.7708101Z # 0 suppress.exe!do_uninit_read (0x00007ff7c109102a )
2020-12-07T05:22:55.7708837Z d:\a\drmemory\drmemory\tests\suppress.c:63
2020-12-07T05:22:55.7709587Z # 1 suppress.exe!do_uninit_cb (0x00007ff7c109160a )
2020-12-07T05:22:55.7710368Z d:\a\drmemory\drmemory\tests\suppress.c:261
2020-12-07T05:22:55.7711114Z # 2 suppress.exe!call_into_foo (0x00007ff7c1091676 )
2020-12-07T05:22:55.7711841Z d:\a\drmemory\drmemory\tests\suppress.c:276
2020-12-07T05:22:55.7712592Z # 3 suppress.exe!mod_ellipsis_test (0x00007ff7c1091745 )
2020-12-07T05:22:55.7713361Z d:\a\drmemory\drmemory\tests\suppress.c:329
2020-12-07T05:22:55.7714067Z # 4 suppress.exe!test (0x00007ff7c109189c )
2020-12-07T05:22:55.7714792Z d:\a\drmemory\drmemory\tests\suppress.c:379
2020-12-07T05:22:55.7715500Z # 5 suppress.exe!main (0x00007ff7c1091919 )
2020-12-07T05:22:55.7716220Z d:\a\drmemory\drmemory\tests\suppress.c:398
2020-12-07T05:22:55.7716712Z Note: @0:00:03.409 in thread 1948
2020-12-07T05:22:55.7717185Z Note: instruction: test %eax %eax
```