Removing `g_hmodCoreCLR` and `g_hThisInst` (#43735)

Removing `g_hmodCoreCLR` and `g_hThisInst`  (#43735)

* g_hmodCoreCLR is Windows-only

* Use 42 in MarkAsThrownByUsWorker()

* replaced GetCLRModule with GetClrModulePathName

* Addded PAL_GetPalHostModule to mscordac_unixexports

* replaced a few cases of g_hThisInst where used to get module path. We can uise `GetClrModulePathName` instead.

* more cases where used to get module path

* unused `GetModuleInst()`

* not using HMODULE in StressLog

* removed mscoree GetModuleInst

* Deleted both  `g_hThisInst` and `g_hmodCoreCLR`

* fix Linux build

* rename `GetModuleBase` ->` GetClrModuleBase`,  it was confusing with other `GetClrModuleBase`

* Fix Linux build

* PR feedback

* Removed hMod variables in Debugger areas

* standalone GC

* cache GetClrModuleBase

* Prevent double-read of `pImageBase`

* fix linker issue

* couple more link order fixes.

* Remove `g_thisModule` in daccess.cpp. Fix typos.