Fix msvc/ecpg_regression.proj for recent ECPG test additions.

Commit 3b7ab438 added some tests that require ecpg to be given the
new "-C ORACLE" switch.  Teach the MSVC build infrastructure about
that.

Michael Paquier

Discussion: https://postgr.es/m/8299.1521154647@sss.pgh.pa.us

src/tools/msvc/ecpg_regression.proj

@@ -33,6 +33,9 @@
   <CreateProperty Value="-C INFORMIX -r no_indicator" Condition="'%(Pgc.FileName)'=='rnull'">
    <Output TaskParameter="Value" PropertyName="ECPGPARAM" />
   </CreateProperty>
+  <CreateProperty Value="-C ORACLE" Condition="'%(Pgc.RelativeDir)'=='$(TESTDIR)\compat_oracle\'">
+   <Output TaskParameter="Value" PropertyName="ECPGPARAM" />
+  </CreateProperty>
   <CreateProperty Value="-c" Condition="'%(Pgc.FileName)'=='array_of_struct'">
    <Output TaskParameter="Value" PropertyName="ECPGPARAM" />
   </CreateProperty>