JNICALL declaration breaks Splash screen functions

A DESCRIPTION OF THE PROBLEM :
The JNICALL (__stdcall) declarations added to the splash screen native source in response to bug #8201226 cause the splash screen function names to be decorated in 32-bit Windows. This way they can't be loaded anymore with GetProcAddress and their simple names (that they still have in 64-bit Windows, because __stdcall is ignored there).

REGRESSION : Last worked in version 8u202

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Call "dumpbin splashscreen.dll /EXPORTS"

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Should show
[...]
         11 0 0001C86A SplashClose
         12 1 0001D863 SplashGetScaledImageName
[...]
etc
ACTUAL -
Shows
[...]
         11 A 0001C868 _SplashClose@0
         12 B 0001D86B _SplashGetScaledImageName@20
[...]
etc

CUSTOMER SUBMITTED WORKAROUND :
Patch the source files, removing the JNICALL declarations in splashscreen_impl.h, splashscreen_impl.c and splashscreen_sys.c before building the JDK.

FREQUENCY : always