Minor cleanup of some SMT2 files

- Replaced `ALL_SUPPORTED` (which is CVC4-specific) with `ALL` (which is
  part of the SMTLIB 2.5+ standard).
- Added `incremental` option in an SMT2 file, which is required for using
  the `push` and `pop` commands in CVC4.

Author: SaswatPadhi

regression/strings/test3/test-bv-to-int-onebyone.smt2

@@ -1,5 +1,6 @@
 (set-option :produce-models true)
-(set-logic ALL_SUPPORTED)
+(set-option :incremental true)
+(set-logic ALL)
 
 (declare-fun s () String)
 (declare-fun s2 () String)

regression/strings/test3/test-bv-to-int.smt2

@@ -1,5 +1,5 @@
 (set-option :produce-models true)
-(set-logic ALL_SUPPORTED)
+(set-logic ALL)
 
 (declare-fun s () String)
 (declare-fun s2 () String)

regression/strings/test3/test-int.smt2

@@ -1,5 +1,5 @@
 (set-option :produce-models true)
-(set-logic ALL_SUPPORTED)
+(set-logic ALL)
 
 (declare-fun s () String)
 (declare-fun s2 () String)