Delete extra copies of context from terms for some proof mode tactics.

tests/proofmode.ref

@@ -118,7 +118,7 @@ Tactic failure: iSpecialize: cannot instantiate (⌜φ⌝ → P -∗ False)%I wi
   ============================
   "H1" : ⌜S (S (S x)) = y⌝
   --------------------------------------□
-  "H2" : ⌜(1 + y)%nat = z⌝
+  "H2" : ⌜1 + y = z⌝
   --------------------------------------∗
   ⌜S (S (S x)) = y⌝
   
@@ -459,11 +459,13 @@ x is already used.
 "iSplit_one_of_many"
      : string
 The command has indeed failed with message:
-Ltac call to "iSplitL (constr)" failed.
-Tactic failure: iSplitL: hypotheses ["HPx"] not found.
+In nested Ltac calls to "iSplitL (constr)" and "iMissingHyps", last call
+failed.
+No matching clauses for match.
 The command has indeed failed with message:
-Ltac call to "iSplitL (constr)" failed.
-Tactic failure: iSplitL: hypotheses ["HPx"] not found.
+In nested Ltac calls to "iSplitL (constr)" and "iMissingHyps", last call
+failed.
+No matching clauses for match.
 "iExact_fail"
      : string
 The command has indeed failed with message:
@@ -519,6 +521,7 @@ In nested Ltac calls to "iPoseProof (open_constr) as (constr)",
 "iPoseProofCore (open_constr) as (constr) (constr) (tactic)",
 "iPoseProofCoreLem (constr) as (constr) before_tc (tactic)", 
 "tac" (bound to spec_tac ltac:(()); [ .. | tac Htmp ]), 
+"tac" (bound to spec_tac ltac:(()); [ .. | tac Htmp ]), 
 "tac" (bound to fun H => iDestructHyp H as pat),
 "iDestructHyp (constr) as (constr)",
 "<iris.proofmode.ltac_tactics.iDestructHypFindPat>",