vlookup - optimize SC_EQUAL and NOT_EQUAL.

Also don't accept partial matches ie. CONTAINS != EQUAL,
for VLOOKUP even if document option "search criteria =, <>
for whole cells" is turned off.

This also adds a new spreadsheet test file vlookup2.fods
with the option "search criteria =,<> for whole cells" turned off,
with VLOOKUP test cases that ensures that partial matches are not
accepted.

Change-Id: Ib1f4781b216431546c3fd6967f22518e86abf36b
Reviewed-on: https://gerrit.libreoffice.org/52589Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>

sc/source/core/data/table3.cxx

@@ -2600,6 +2600,11 @@ public:
 
                         if (nIndex < 0)
                             nStrPos = -1;
+                        else if (rEntry.eOp == SC_EQUAL ||
+                                 rEntry.eOp == SC_NOT_EQUAL)
+                        {
+                            nStrPos = pCellStr == pQuer ? 0 : -1;
+                        }
                         else
                         { // OUString::indexOf
                             nStrPos = rtl_ustr_indexOfStr_WithLength(
@@ -2629,10 +2634,14 @@ public:
                     switch (rEntry.eOp)
                     {
                     case SC_EQUAL:
+                        bOk = ( nStrPos == 0 );
+                        break;
                     case SC_CONTAINS:
                         bOk = ( nStrPos != -1 );
                         break;
                     case SC_NOT_EQUAL:
+                        bOk = ( nStrPos != 0 );
+                        break;
                     case SC_DOES_NOT_CONTAIN:
                         bOk = ( nStrPos == -1 );
                         break;