VS: Remove flag table entries for Fortran /Z* flags

These were included when the Fortran flag table was first created by
commit 10c91ded4f (ENH: add support for Intel Fortran Visual studio IDE,
2008-04-30, v2.8.0~2227), but they map to fields not actually supported
by the IDE.  Remove their table entries.

Instead use just `/debug:minimal` and `/debug:full` to control debug
information level in VS Intel Fortran.  Let flags like `/Z7` pass
through as raw additional options because they have no corresponding IDE
property and can be used to complement the supported options.

Fixes: #21340

Source/cmLocalVisualStudio7Generator.cxx

@@ -275,10 +275,9 @@ cmVS7FlagTable cmLocalVisualStudio7GeneratorFortranFlagTable[] = {
   { "SuppressStartupBanner", "nologo", "SuppressStartupBanner", "true", 0 },
   { "SourceFileFormat", "fixed", "Use Fixed Format", "fileFormatFixed", 0 },
   { "SourceFileFormat", "free", "Use Free Format", "fileFormatFree", 0 },
-  { "DebugInformationFormat", "Zi", "full debug", "debugEnabled", 0 },
   { "DebugInformationFormat", "debug:full", "full debug", "debugEnabled", 0 },
-  { "DebugInformationFormat", "Z7", "c7 compat", "debugOldStyleInfo", 0 },
-  { "DebugInformationFormat", "Zd", "line numbers", "debugLineInfoOnly", 0 },
+  { "DebugInformationFormat", "debug:minimal", "line numbers",
+    "debugLineInfoOnly", 0 },
   { "Optimization", "Od", "disable optimization", "optimizeDisabled", 0 },
   { "Optimization", "O1", "min space", "optimizeMinSpace", 0 },
   { "Optimization", "O3", "full optimize", "optimizeFull", 0 },