Fix build breakage on high-processsor machines (dotnet/coreclr#12114)

Fix build breakage on high-processsor machines (dotnet/coreclr#12114)

The build calls `make -j $NumProc`. This breaks on machines with a high
number of procesors (such as 25).

To reproduce this on any machine, edit build.sh and change

    buildTool install -j $NumProc

to

    buildTool install -j 100

The error trace looks like this:

    In file included from coreclr/bin/obj/Linux.x64.Debug/Generated/eventpipe/dotnetruntime.cpp:12:
    In file included from coreclr/src/vm/common.h:306:
    In file included from coreclr/src/vm/eepolicy.h:15:
    In file included from coreclr/src/vm/vars.hpp:70:
    In file included from coreclr/src/vm/eeprofinterfaces.h:19:
    In file included from coreclr/src/inc/profilepriv.h:128:
    In file included from coreclr/src/inc/profilepriv.inl:18:
    In file included from coreclr/src/vm/eetoprofinterfaceimpl.h:23:
    coreclr/src/inc/eventtracebase.h:306:10: fatal error: 'clretwallmain.h' file not found

It turns out that the eventpipe code has a dependency on
clretwallmain.h. src/CMakeLists.txt points out that clretwallmain.h is a
generated file. But there's no actual dependency between the eventpipe
target and the header file(s).

Fix that by fixing the generator script to insert an explicit dependency
between 'eventpipe' module and 'GeneratedEventingFiles' module.

Commit migrated from https://github.com/dotnet/coreclr/commit/f14cffc86b49cb803a6ed8e5a864f8c0c7b87f33