JSCOnly build broken on linux

https://bugs.webkit.org/show_bug.cgi?id=274115

Unreviewed build fix.

https://commits.webkit.org/278554@main moved platform-specific headers
to the platform cmake files, but did not update PlatformJSCOnly.cmake
with a pair of required headers.

* Source/WTF/wtf/PlatformJSCOnly.cmake:

Canonical link: https://commits.webkit.org/278741@main

Source/WTF/wtf/PlatformJSCOnly.cmake

@@ -93,6 +93,10 @@ elseif (CMAKE_SYSTEM_NAME MATCHES "Linux")
 
         unix/MemoryPressureHandlerUnix.cpp
     )
+    list(APPEND WTF_PUBLIC_HEADERS
+        linux/CurrentProcessMemoryStatus.h
+        linux/ProcessMemoryFootprint.h
+    )
 elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
     list(APPEND WTF_SOURCES
         generic/MemoryFootprintGeneric.cpp